Dermatome



J. D. REESE DERMATOME Aug. 16, 1949.

2 Sheets-Sheet 1 Filed July '7, 1 947 INVENTOR. J'QAN ID. [ZEEsE 1949-J. D. lEEsE 2,479,185

DERMATOME Filed July 7, 1947 2 Sheets-Sheet 2 i E il 7G .EIQ, 7 ll; 74

INVENTOR. J34: 1 E5555 BY ATTOEA/EV.

Patented Aug. 16, 1949 John 1). Reese, Philadelphia, Pa. ApplicationJuly 7, 1947, Serial No. 759,329

. 1 1 This invention relates to surgery, more particularly to skingrafting, and has for an object to provide an improved dermatome forcutting skin grafts.

In applicants copending application, Serial No. 618,523, filed September25, 1945, now Patent No. 2,442,434 granted June 1, 1948, there is 2Claims. (Cl. 128-305) disclosed a dermatome of the type comprisinga bodymember having a convex working face and a graft cutting member supportedby the body member for cutting movement parallel to, and at apredetermined distance from, the convex face,-this dermatcme includingmechanism for temporarily securing thereon a graft transfer member, fordrawing the graft transfer member taut against the convex working faceof the body member and for maintaining the tautness of the grafttransfer member.

Thus, this prior disclosure involved the use of threeelements and theirrespective functions, as follows: aclamp for holding one end of thegraft transfer member to the dermatome, a rotatable shaft for holdingthe other end of the graft transfer member and for drawing it tauttogether with a cam for obtaining a finer adjustment of the tautness,and ratchets and pawls associated with the shaft and the cam forretaining the degree of tautness obtained.

In the invention of the present application, applicant has greatlysimplified the mechanism of the second and third elements by combiningthem in a single element which performs the two functions of'these twopreviously-proposed elements. To this end, applicant provides a worm andgear drive for the rotatable shaft which holds the second endof thegraft transfer member, this worm drive not only obtaining, through therotatable shaft, and without the use of the cam, arbitrarily smalldegrees of tautness in the graft transfer member, but also retaining anydegree of tautness obtained, inasmuch as the worm prevents any reverserotation of the shaft other than that imparted to it through the wormitself when it is desired to release the graft transfer member aftercutting of the graft.

Therefore, another object of the invention is to provide, in a dermatomeof the type adapted to have temporarily secured thereto a flexible grafttransfer member, a single means for drawing taut such graft transfermember and retaining it at the degree of tautness selected.

A further object of the invention is to provide, in a dermatome of thetype adapted to have temporarily secured thereon a graft transfermember, means for securing one end of such graft transfer member to thedermatome and a rotatable shaft to which the other end of the grafttransfer member may be secured together'with a gear on the shaft and aworm cooperating therewith and by rotation of which the shaft may beturned to draw the graft transfer member taut against the working faceof the dermatome.

e i. Thesezand other objects are effected by the inventionas will beapparent from the following description and claims, taken in accordancewith the accompanying drawings, forming a part of this application, inwhich:

Fig. 1 is a front elevational view, partially in section, of a dermatomeconstructed in accordance with the present invention;

Fig. 2 is a plan view of the dermatome shown in Fig. 1; e Fig. 3 is afragmentary side elevational view showing details of the worm and geardrive for the rotatable shaft; and taken along the line III-III of Fig.2, looking in the direction indicated by the arrows;

Fig. 4 is a transverse sectional view, taken along the line IV--IV ofFig. 2, looking in the direction indicated by the arrows;

Fig. 5 is afragmentary side elevational view showing details of theblade-supporting structure; -i

Fig.- 6 is a fragmentary plan view showing details of the clampingmechanism; and

Fig. 7 is a side elevational view of a crank handle by which the wormmechanism may be operated.

Referring now to the drawings in greater detail, particularly to Figs. 1and 4 thereof, the reference character It! indicates, in its entirety, adermatome having a body member If comprised bya pair of spaced parallelside plates l2 and I3 of generally semi-circular shape, joined alongtheir curved edges by a concave-convex bottom plate l4. Preferably, theside plates l2 and 13 are provided 'with inwardly-directed flanges l5against which the bottom plate M rests. These flanges l5 not onlyprovide relatively extensive areas of engagement with the bottom plate,but also'serve to stiffen the side plates and prevent deformationthereof.

Each side plate includes an upwardly-extending ear [6 having an openingI! therethrough whose center coincides with the center of revolution ofthe concave working surface l8 of the bottom plate M. A pair of bushingsl8 are mounted in the openings I! with flanges 2| abutting the outersurfaces of the side plates. A tubular'handle 22 bridges the spacebetween the side plates and is supported on the inwardlyprojectingbushings IS.

A shaft 23 is journaled in the bushings l9 for both rotary andreciprocatory movement relative to the body member II and has fixedlysecured thereto a yoke, indicated in its entirely by the referencecharacter 25. The yoke 25 includes a pair of parallel posts or arms 26,secured one at each end of the shaft 23 by tapered dowel pins 21 (Figs.2 and 4) provided with threaded portions 28 threaded into bosses 29 onthe posts 26 and having knurled finger pieces 30 for rotation of thepins. The other ends of the posts are joined by an integral cross bar 33hav ing a fiat outer surface 34, between which and i an opposed flatsurface on a blade clamping bar 36, a graft-cutting blade or knife 3'!is. adapted to be clamped (Figs. 4 and. 5). As clearly shown in Fig. 4,the cutting edge of the blade 31 is positioned in close proximity to theconvex working face I8 of the dermatome body member Ii, and its spacingwith respect thereto may be varied by changing a shim 38, between theblade and the surface 34 on the yoke cross bar 33, to one of greater orlesser thickness.

The blade-clamping bar 35 has a pair of studs extending perpendicularlyfrom its face 35 and extending through a pair of matingopenings M in theouter ends 42 of the posts 26, which outer ends are offset with respectto the re.- mainder of the, posts with the result that the free ends ofthe studs 40 project beyond the post outer ends 42 and threadedlyreceive knurled finger pieces 63, by which the blade-clamping bar 36 maybe drawn into clamping relation to the blade 31..

Preferably, each post 26 is provided with a projecting lip 45restraining the fingerpieces 43 against axial movement and insuring thatrota-.

tion of the finger pieces will produce movement of the blade-clampingbar 3.5 towards or away from the yoke cross bar 33. This action ispar-.- ticularly desirable inasmuch as the posts are usually in theposition illustrated in Fig. 5 when the blade is being. assembled orremoved, and without the lips 55; the bladeeclamping bar would not stayspaced from the cross bar to permit of ready assembly of the blade andshim. The shim may be provided with a tab 46 on which its thickness in.thousandths of an inch is indicated,'so

thatthe thickness of the graft that will be out can be noted at anytime.

One of the posts 23 is provided with a handle 4'1, by which the entireyoke 25, its shaft .23 and t e blade may be simultaneously reciprocatedand rotated to move the blade, with a cutting motion relative to theworking face of the body member, and at a predetermined distancetherefrom.

The mechanism for retaining a. graft transfer member taut against theconvex working face l8 includes clamp 5e mounted for limited pivotalmovement on, the pin 5| into and out. of clamping engagement with theend A of a graft transfer member T (Figs. 2-, 4 and 6). The grafttransfer member-engaging edge of the clamp 50 is toothed or serrated, asat 52, to bite into the transfer member and insure that the latter doesnot pull out from between the clamp and the inner sur-l face of the bodymember.

To retain the clamp in clampingposition there is provided arearwardly-extending arm 5.4, on top of which is a second arm. 55;,pivoted to. the rear end of the first arm-54, as c.1156; When the era-15.5-. is moved against. the adiacent. side wall 13, as shown in fulllines in Fig. 6, it lies beneath a pin 51 which projects from the sidewall l3, whereby the clamp 5|] is prevented from pivoting about its pin5| from clamping position. To release the clamp, the upper arm is movedaway from the side wall I3 to the position indicated in Fig. 6 by thedot-dash lines, which movement is limited by a downwardly-extending lug58 thereon (Fig. 4) To assist in moving the upper arm, the latter has anupwardly-extending finger piece or tab 59, which may be easily engagedby the fingers of the operator. The clamp 50 has a rearwardly-extendinghandle 60 by which it may be easily moved to and from clamping position.

The opposite end B of the graft transfer member T is received in theslot 63 of a spool 64 journaled in bearin s 65 carried by the bodymember side walls l2 and I3. One of the spool journals projectsoutwardly beyond the adjacent side wall l3, as at 66, and has securedthereon a gear 61 meshing with a worm 68 secured on the shaft 69. Thisshaft 69 is mounted in a gear housing H, attached to the side wall l3 byscrews 12 and en.- closin the worm 63 and gear 67. One end of the wormshaft 69 projects through a top wall of the housing and is slotted, asat 13, for reception of a pin "M. extending diametrically of a socket I5provided in the head 16 of a crank-type wrench if, havin a handle 18.

When the worm shaft 59 is rotated in a clockwise direction by means ofthe crank 11, the spool 64 will be turned counter-clockwise, as viewedin Fig, a, thereby tightening the graft transfer mem her. It will beapparent that with the Worm drive, the spool 54 can be given any desireddeprevent counter rotation of the spool and consequent reduction intautness of the graft transfer member. The worm itself locks the spoolagainst rotation.

Application Serial No. 79,255 filed March 2, 1949, has been divided outof this application, the divisional application covering blade adjustingmechanism shown in Fig. 5.

While the invention has been shown in but one form, it will be obviousto those skilled in the art that it is not so limited, but issusceptible of various changes and modifications without departing fromthe spirit thereof.

What is claimed is:

1. A dermatome comprisin a body member having a pair of side wallsjoinedadjacent an edge by a bottom wall having a convex outer surfaceagainst which a flexible graft-transfer member is adapted to be heldtaut, means for holding one end of the graft-transfer member stationaryrelative to the body member,' bearing structure carried by the pair ofsidewalls, a first shaft journaled in said bearing structure forrotation relative to the body member and having means for holding theother end of the graft-transfer member, whereby rotation of the shaftwill draw the graft-transfer member taut against the com vex outersurface ofthe body member bottom wall, said shaft having one of itsterminal portions disposed exteriorly of the body member, a gearsec-uredon said one terminal portion; a see 5 6 0nd shaft supported bythe body member, a worm secured on said second shaft and coacting withEF RENCES CITED the gear on the terminal portion of the first shaft, Thi no i f n f whereby said first shaft may be rotated by the file i 2:5ere ces are 0 record m the second shaft to draw the graft-transfer member 5 taut, said coacting worm and gear preventing UNITED STATES PATENTScounter rotation of the first shaft due to torque Number Name Dateapplied thereto by the tautness of the graft- 2,217,923 silverman Oct.15, 1940 transfer member.

2. Structure as specified in claim 1, including 10 a handle for rotatingthe second shaft.

JOHN D. REESE.

2,424,584 Reese July 29, 1947

